Anno 1404 belongs to my top favourite games ever, so I'm very excited to read this news.
On the other hand, I agree fully with the posts above expressing trepidation about Ubisoft's DRM being involved. Now this is my view on Ubisoft's DRM, and no amount of flaming from anyone is going to change that: If I'm forced to accept their online-always-regardless-of-game-mode crap, then I'm just not going to buy it, just as I didn't buy Settlers 7 or Silent Hunter 5.
But that's OK by me, there's lots of other stuff to get. As a company, it's their right to implement any anti-pirate mechanisms they like, and as a customer it's my right to say: get stuffed!